Struts2学习笔记NO.1——结合Hibernate完成查询商品类别简单案

　　　　Struts2学习笔记一结合Hibernate完成查询商品类别简单案例（工具IDEA）1.jar包准备

Hibernate+Struts2 jar包

struts的jar比较多,可以从Struts官方提供的demo中拿到必要的jar就行. 在apps/struts2-blank项目下

2.数据库准备

 1 /* 2 Navicat MySQL Data Transfer 3  4 Source Server         : GaGa 5 Source Server Version : 50549 6 Source Host           : localhost:3306 7 Source Database       : day38hibernate 8  9 Target Server Type    : MYSQL10 Target Server Version : 5054911 File Encoding         : 6500112 13 Date: 2018-01-26 21:04:3614 */15 16 SET FOREIGN_KEY_CHECKS=0;17 18 -- ----------------------------19 -- Table structure for t_category20 -- ----------------------------21 DROP TABLE IF EXISTS `t_category`;22 CREATE TABLE `t_category` (23   `cid` int(11) NOT NULL AUTO_INCREMENT,24   `cname` varchar(255) DEFAULT NULL,25   PRIMARY KEY (`cid`)26 ) ENGINE=InnoDB AUTO_INCREMENT=13 DEFAULT CHARSET=utf8;27 28 -- ----------------------------29 -- Records of t_category30 -- ----------------------------31 INSERT INTO `t_category` VALUES ('1', '水果');32 INSERT INTO `t_category` VALUES ('2', '电子产品');33 INSERT INTO `t_category` VALUES ('3', '食物');34 35 -- ----------------------------36 -- Table structure for t_product37 -- ----------------------------38 DROP TABLE IF EXISTS `t_product`;39 CREATE TABLE `t_product` (40   `pid` int(11) NOT NULL AUTO_INCREMENT,41   `pname` varchar(255) DEFAULT NULL,42   `price` double DEFAULT NULL,43   `cid` int(11) DEFAULT NULL,44   PRIMARY KEY (`pid`),45   KEY `FKq8yr5sflwtcj3jqp58x0oy7lx` (`cid`),46   CONSTRAINT `FKq8yr5sflwtcj3jqp58x0oy7lx` FOREIGN KEY (`cid`) REFERENCES `t_category` (`cid`)47 ) ENGINE=InnoDB AUTO_INCREMENT=121 DEFAULT CHARSET=utf8;48 49 -- ----------------------------50 -- Records of t_product51 -- ----------------------------52 INSERT INTO `t_product` VALUES ('1', '葡萄', '8', '1');53 INSERT INTO `t_product` VALUES ('2', '李子', '4.5', '1');54 INSERT INTO `t_product` VALUES ('3', '柚子', '16.8', '1');55 INSERT INTO `t_product` VALUES ('4', '樱桃', '14.8', '1');56 INSERT INTO `t_product` VALUES ('5', '橙子', '5.8', '1');57 INSERT INTO `t_product` VALUES ('6', '苹果', '6', '1');58 INSERT INTO `t_product` VALUES ('7', '西瓜', '2', '1');59 INSERT INTO `t_product` VALUES ('8', '梨子', '3.5', '1');60 INSERT INTO `t_product` VALUES ('9', '蓝莓', '10', '1');61 INSERT INTO `t_product` VALUES ('10', '香蕉', '2', '1');62 INSERT INTO `t_product` VALUES ('11', 'iPhone6s', '6500', '2');63 INSERT INTO `t_product` VALUES ('12', 'iPhone4s', '3000', '2');64 INSERT INTO `t_product` VALUES ('13', 'Mac', '18000', '2');65 INSERT INTO `t_product` VALUES ('14', '战神', '6600', '2');66 INSERT INTO `t_product` VALUES ('15', 'iPhone5s', '4300', '2');67 INSERT INTO `t_product` VALUES ('16', 'iPhone7', '8000', '2');68 INSERT INTO `t_product` VALUES ('17', '拯救者', '8000', '2');69 INSERT INTO `t_product` VALUES ('18', 'iPhone6', '5000', '2');70 INSERT INTO `t_product` VALUES ('19', 'iPhone5', '3600', '2');71 INSERT INTO `t_product` VALUES ('20', 'iPhone4', '2500', '2');72 INSERT INTO `t_product` VALUES ('21', '羊肉', '56', '3');73 INSERT INTO `t_product` VALUES ('22', '猪肉', '17', '3');74 INSERT INTO `t_product` VALUES ('23', '鱼', '7', '3');75 INSERT INTO `t_product` VALUES ('24', '上海青', '3.5', '3');76 INSERT INTO `t_product` VALUES ('25', '牛肉', '22', '3');77 INSERT INTO `t_product` VALUES ('26', '白菜', '4', '3');78 INSERT INTO `t_product` VALUES ('27', '辣条', '2', '3');79 INSERT INTO `t_product` VALUES ('28', '面包', '6', '3');80 INSERT INTO `t_product` VALUES ('29', '鸡肉', '8.6', '3');81 INSERT INTO `t_product` VALUES ('30', '方便面', '3.5', '3');

数据库准备3.配置文件准备

　　1）Category映射文件配置

 1 <?xml version="1.0" encoding="UTF-8"?> 2 <!DOCTYPE hibernate-mapping PUBLIC  3     "-//Hibernate/Hibernate Mapping DTD 3.0//EN" 4     "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd"> 5 <hibernate-mapping> 6     <class name="com.gaga.bean.Category" table="t_category"> 7         <id name="cid" column="cid"> 8             <generator class="native"/> 9         </id>10         <property name="cname" column="cname"/>11         12         <!--配置多方(Set)13             一,通过Set标签配置多方14                 1.1name属性: 一方类里面Set集合的变量名15           -->16         <set name="products" fetch="select" lazy="false">17             <!--1.2 column: 外键的列名  -->18             <key column="cid"/>19             <!--1.3  class: 对方类的全限定名  -->20             <one-to-many class="com.gaga.bean.Product"/>21         </set>22         23     </class>24 </hibernate-mapping>

Category映射文件配置

　　2）Product映射文件配置

 1 <?xml version="1.0" encoding="UTF-8"?> 2 <!DOCTYPE hibernate-mapping PUBLIC  3     "-//Hibernate/Hibernate Mapping DTD 3.0//EN" 4     "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd"> 5 <hibernate-mapping> 6     <class name="com.gaga.bean.Product" table="t_product"> 7         <id name="pid" column="pid"> 8             <generator class="native"/> 9         </id>10         <property name="pname" column="pname"/>11         <property name="price" column="price"/>12         13         <!--一, 配置一方14              name属性: 多方类里面一方对象的属性名15              class属性: 一方类的全限定名16              column属性: 外键的列名17          -->18         <many-to-one name="category" class="com.gaga.bean.Category" column="cid" />19 20     </class>21 </hibernate-mapping>

Product映射文件配置4.配置核心文件hebernate.cfg.xml

 1 <?xml version="1.0" encoding="UTF-8"?> 2 <!DOCTYPE hibernate-configuration PUBLIC 3     "-//Hibernate/Hibernate Configuration DTD 3.0//EN" 4     "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd"> 5 <hibernate-configuration> 6     <session-factory> 7         <!--一, 必配(驱动, 数据库的路径, 用户名, 密码 , 方言)  --> 8         <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property> 9         <property name="hibernate.connection.url">jdbc:mysql:///day38hibernate</property>10         <property name="hibernate.connection.username">root</property>11         <property name="hibernate.connection.password">123</property>12         <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>13         14          <!--二, 选配  -->15          <!--2.1 显示sql语句  -->16          <property name="hibernate.show_sql">true</property>17          <!--2.2 格式化sql  -->18          <property name="hibernate.format_sql">true</property>19          <!--2.3 配置hibernate自动创建表  -->20          <property name="hibernate.hbm2ddl.auto">update</property>21          <!--2.4 集成c3p0  -->22          <property name="hibernate.connection.provider_class">org.hibernate.c3p0.internal.C3P0ConnectionProvider</property>    23          <property name="hibernate.c3p0.max_size">10</property>24          25           <!--2.6 打开session和本地线程绑定  -->26         <property name="hibernate.current_session_context_class">thread</property> 27          28          <!--三, 导入映射文件 resource映射文件的路径  resource属性就是映射文件的路径  -->29          <mapping resource="com/gaga/bean/Category.hbm.xml"/>30          <mapping resource="com/gaga/bean/Product.hbm.xml"/>31     32     </session-factory>33 </hibernate-configuration>

核心配置文件

5.Struts2.xml配置

 1 <?xml version="1.0" encoding="UTF-8"?> 2  3 <!DOCTYPE struts PUBLIC 4         "-//Apache Software Foundation//DTD Struts Configuration 2.3//EN" 5         "http://struts.apache.org/dtds/struts-2.3.dtd"> 6  7 <struts> 8     <package name="category" extends="struts-default" namespace="/"> 9         <action name="category_*" class="com.gaga.servlet.CategoryAction" method="{1}">10             <result name="success">list.jsp</result>11             <result name="error">msg.jsp</result>12         </action>13     </package>14 15 </struts>

Struts2.xml

6.utils导入

package com.gaga.utils;import org.hibernate.Session;import org.hibernate.SessionFactory;import org.hibernate.cfg.Configuration;/** *作用:  *1. 提供session *2. 保证SessionFactory全局只有一个  * */public class HibernateUtils {        private static  Configuration configuration = null;    private static  SessionFactory sessionFactory = null;                /**     * 保证SessionFactory全局只有一个      */    static{         //1. 创建配置对象, 进行配置         configuration = new Configuration();         configuration.configure();         //2. 构建session工厂(相当于连接池)  内置连接池 ---> c3p0 dbcp 阿里druid  光连接池          sessionFactory = configuration.buildSessionFactory();    }            private HibernateUtils() {            }    //每次都是获得的新的session,数据库操作完成之后需要close    public static Session openSession(){         //3. 获得session (相当于连接)         Session session = sessionFactory.openSession();        return session;    }             //4. 从本地线程获得Session(前提是你已经在核心配置文件里面配置了 <property name="hibernate.current_session_context_class">thread</property>)    //从本地线程获得的session(第一次没有, 获得新的存到本地线程里面,下一次直接从本地线程获得 ), 不需要close    public static Session getCurrentSession(){        Session session = sessionFactory.getCurrentSession();        return session;    }    }

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7.编写Action类

package com.gaga.servlet;import com.gaga.bean.Category;import com.gaga.service.CategoryService;import org.apache.struts2.ServletActionContext;import javax.servlet.http.HttpServletRequest;import java.util.List;public class CategoryAction {    public String findAll() {        //1. 获得请求参数        //2. 调用业务        try {             System.out.println("CategoryAction接受了请求");            CategoryService categoryService = new CategoryService();            List<Category> list = categoryService.findAll();            //3. 把list存到域里面, 转发页面            ServletActionContext.getRequest();            HttpServletRequest request = ServletActionContext.getRequest();            request.setAttribute("list", list);            return "success";        } catch (Exception e) {            e.printStackTrace();            HttpServletRequest request = ServletActionContext.getRequest();            request.setAttribute("msg", "错误");            return "error";        }    }}

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8.编写service层

 1 package com.gaga.service; 2  3 import com.gaga.bean.Category; 4 import com.gaga.dao.CategoryDao; 5  6 import java.util.List; 7  8 public class CategoryService { 9     public List<Category> findAll() {10         CategoryDao categoryDao = new CategoryDao();11 12         return categoryDao.findAll();13     }14 }

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9.编写dao层

 1 package com.gaga.dao; 2  3 import com.gaga.bean.Category; 4 import com.gaga.utils.HibernateUtils; 5 import org.hibernate.Session; 6 import org.hibernate.Transaction; 7  8 import java.util.List; 9 10 public class CategoryDao {11     public List<Category> findAll() {12         Session session = HibernateUtils.getCurrentSession();13         Transaction transaction = session.beginTransaction();14         List<Category> list = null;15 16         list = session.createCriteria(Category.class).list();17 18         transaction.commit();19 20         System.out.println("CategoryDao结果list:---"+list);21         return list;22     }23 }

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10.前端jsp页面布置

<%@ page language="java" contentType="text/html; charset=UTF-8"    pageEncoding="UTF-8"%><%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><!-- saved from url=(0044)http://localhost:8080/day41C_Product/product --><html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>Insert title here</title><style>#BAIDU_DSPUI_FLOWBAR,.adsbygoogle,.ad,div[class^="ad-widsget"],div[id^="div-gpt-ad-"],a[href*="cpro.baidu.com"],a[href*="@"][href*=".exe"],a[href*="/?/"][href*=".exe"],.adpushwin{display:none!important;max-width:0!important;max-height:0!important;overflow:hidden!important;}</style></head><body><center><h1>类别信息</h1><table border="1px" width="500px" cellspacing="0"><tbody><c:forEach items="${list }" var="c"><tr><td colspan="3" style="color: red; font-size: 30px">分类名称:${c.cname }</td ></tr><tr><td>商品ID</td><td>商品名称</td><td>商品价格</td></tr> <c:forEach items="${c.products}" var="p"><tr><td>${p.pid }</td><td>${p.pname }</td><td>${p.price }</td></tr></c:forEach></c:forEach></tbody></table></center></body></html>

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11.发布到Tomcat，结果显示

『 不可能 』只存在於蠢人的字典里